Oxidation is the main reason for instability of the edible oils and causes change in chemical and nutritional properties of the oils. Aldehydes are amongst the products of the oxidation and are well-known for being health risks. The commercial methods to oxidation-stabilize the edible oils are time consuming, expensive and demand preparation. Moreover, using toxic and reactive chemical compounds and solvents are other disadvantages of these methods. Solid-phase microextraction (SPME) is a new technique which eliminates the need for such harmful solvents and compositions. However, one of the main drawbacks of the SPME methods is the cost-prohibitive, brittle fibers that are used as sorbents. The present application discloses a polypyrrolelgraphene oxide nanocomposite coated fiber located in a capillary tube reinforced by vacuum system for assessment of oxidative stability of edible oils.